3-amino-3-carbalkoxy-4-hydroxy-2-oxo-4-phenyl-1,2,3,4-tetrahydroquinolines

ABSTRACT

PROCESS FOR THE PREPARATION OF BENZODIAZEPIN-2-ONES COMPRISING EFFECTING RING EXPANSION OF THE NOVEL 2-OXO-3AMINOQUINOLINE INTERMEDIATES VIA ACID OR HEAT TREATMENT. THE END PRODUCTS ARE USEFUL AS SEDATIVES, TRANQUILIZERS, ANTI-CONVULSANTS AND MUSCLE RELAXANTS.

United States Patent O1 ice U.S. c1. 260- 287 R p 7 Claims ABSTRACT OF THE DISCLOSURE Process for the preparation of 'benzodiazepin 2-ones comprising effecting ring expansion of the novel 2-oXo-3- aminoquinoline intermediates via acid or heat treatment.

The end products are useful as sedatives, tranquilizers,

anti-convulsants and muscle relaxants.

RELATED APPLICATIONS This application is a divisional of co-pending application S.N. 1,843 filed Jan. 9, 1970, now U.S. Pat. 3,657,223 issued Apr. 18, 1972.

DESCRIPTION OF THE INVENTION This invention relates to novel processes for the preparation of benzodiazepines and to novel intermediates therefor. The benzodiazepines to which the invention relates are selected from the group consisting of compounds of the formula wherein R is hydrogen, lower alkyl or dilower alkylamino-lower alkyl; R ishydrogen or the group CO- lower alkyl or -COOA wherein A is the cation of a base; R is phenyl, mono-halophenyl or pyridyl; and R is hydrogen, halogen or nitro.

As used herein, either alone or in combination, the term lower alkyl" comprehends straight or branched chain hydrocarbon groups having from 1-7 carbon atoms, preferably 1-4 carbon atoms, such as methyl, ethyl, propyl,

and the like. The term halogen represents all four forms thereof, i.e., fluorine, chlorine, bromine and iodine, unless expressly indicated otherwise.

When R is the cation of a base, said cation can be derived from any suitable base. Representative of suitable bases are alkali metal hydroxides such as sodium hydroxide and the like, alkaline earth metal hydroxides such as triethyl amine and the like, and ammonium hydroxide.

A preferred class of compounds prepared according to the process of the invention are those of the Formula'I wherein R is hydrogen or lower alkyl, most preferably methyl, R is hydrogen, R is phenyl, halophenyl, with the halogen atom preferably positioned in the 2-position 3,772,305 Patented Nov. 13, 1973 of the phenyl ring, or pyridyl, preferably attached to the benzodiazepine nucleus at the 2-position thereof, and R is halogen, preferably chlorine, or nitro, i.e., compounds of the formula 1 13 wherein R is hydrogen or lower alkyl, preferably methyl, R is halogen, preferably chlorine, or nitro, and R is as described above, most preferentially where selected from the group consisting of phenyl, (2-halophenyl) or 2- pyridyl.

Another preferred class of compounds prepared according to the process of the present invention are those of the Formula I wherein R is a dimethylaminoethyl group and R is a Z-fluorophenyl group, i.e., compounds of the formula CHR:

, wherein R and R are as described above.

A particularly preferred aspect of the present invention results in the preparation of 7-chloro-5-phenyl-l-methyl- 1,3-dihydro-2H-1,4-benzodiazepin-2-one, 7-nitro-5-phenyl- 1,3 dihydro-2H-1,4-benzodiazepin-2-one and 7-chloro-1- (diethylaminoethyl) 2H-1,3-dihydro-5-(2-fluorophenyl)- 2H-1,4-benzodiazepin-2-one.

One novel process aspect of the present invention involves effecting ring expansion of a compound of the general formula 0 C O 0lower alky wherein R R and R are as described above.

or acid addition salts thereof with a pharmaceutically acceptable acid, via acid or thermal treatment thereof to produce a compound of Formula I above wherein R is -COO-lower alkyl (i.e., carbalkoxy); that is a compound of the formula wherein R R and R are as described above.

If desired, the carbalkoxy group appearing in the 3-position of the compounds of Formula Ic above can be saponified to the corresponding compound of Formula I above wherein R is COOA where A is as above. The so-obtained compounds of Formula I wherein R is a COO- lower alkyl grouping or a COOA grouping where A is as above can be converted into the corresponding compound of Formula I wherein R is hydrogen by decarboxylation.

When a compound of Formula .11 above is treated with acid to prepare the corresponding compound of Formula I wherein R is -COO-lower alkyl (i.e. the compound of Formula Ic), the reaction is expediently carried out in the presence of an inert organic solvent. Suitable inert organic solvents for the purpose of this aspect of the present are hydrocarbons such as benzene, toluene and the like, and chlorinated hydrocarbons such as chloroform, carbon tetrachloride and the like.

Further, when a compound of Formula II above is treated with acid to effect ring expansion thereof to yield the corresponding compound of Formula Ic, temperature and pressure are not critical to the successful performance of this process aspect. Thus, the reaction can be conducted at temperatures from about room temperature to about the reflux temperature of the reaction mixture, but is preferably effected with the application of heat, most preferably at about the reflux temperature of the reaction mixture.

Suitable acids for the purposes of this process aspect of the present invention include organic and inorganic acids, for example, alkane carboxylic acids such as formic acid, acetic acid, propionic acid and the like, aromatic acids such as benzoic acid and hydrohalic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid and the like. The amount of acid is not critical, but a complete protonation of the amine nitrogen in the starting material should be avoided. When using acetic acid, this can also serve as the solvent. The acid can also be employed in the form of an acid addition salt such as pyridine hydrochloride.

In a further process aspect of the present invention, the compounds of Formula II above can be converted into compounds of Formula Ic above by heating said compounds in the absence of an acid. This thermal treatment to effect ring expansion of the Formula II compounds can be accomplished in the presence or absence of an inert organic solvent. When the conversion is accomplished in the presence of an inert organic solvent, the reaction mixture should be heated to temperatures between 40 C. and the reflux temperature of the reaction mixture. When the conversion is accomplished by merely heating the compounds of Formula II in the absence of an inert organic solvent, the compounds should be heated to temperatures between about 100 and 200 C.

Suitable inert organic solvents for the purposes of this aspect of the present invention include hydrocarbons such as benzene, toluene and the like and chlorinated hydrocarbons such as chloroform, carbon tetrachloride and the like.

The compounds of Formula Ic above are known and can be saponified using conventional techniques to obtain the corresponding compounds of Formula I above wherein R is COOA and A is as above. For example, the saponification of a Formula Ic compound can be effected by treating said compounds with a base, such as an alkali hydroxide, e.g. sodium hydroxide, potassium hydroxide and the like, an alkaline earth hydroxide, e.g. calcium hydroxide and the like, a tertiary organic base such as triethylamine and the like, or ethanolamine. The saponification of a Formula Ic compound can also be effected by treating said compound with an acid. When an acid is used as the saponification agent, saponification and decarboxylation may occur simultaneously so as to produce a compound of Formula I above wherein R is hydrogen.

If desired, the compounds of Formula I above wherein 4 R is COO-lower alkyl or COOA and A is as above can also be decarboxylated using conventional techniques to produce the corresponding compounds of Formula I wherein R is hydrogen. The decarboxylation of a Formula I compound wherein R is COOA and A is as above can be accomplished simply by allowing a solution of said compound to stand, or by heating or acidifying the compound in solution. This decarboxylation of the saponified compound occurs slowly upOn standing, more quickly on heating and spontaneously upon acidification. The decarboxylation of the Formula I compounds wherein R is COO-lower alkyl is accomplished by first saponifying said compound, i.e. by either acid or base treatment, and then decarboxylating the saponified product as described above.

If the ring enlargement of a compound of Formula II above to produce the corresponding compound of Formula I above is effected via acid treatment and if the acid employed is in an aqueous solution, then the saponification and decarboxylation of the carbalkoxy group at R occur in situ during the reaction and one can proceed directly to compounds of Formula I wherein R is hydrogen.

The compounds of Formula II above are novel and as such form a part of the invention. These compounds can be prepared following a variety of procedures. In one such procedure, the compounds of Formula II can be prepared by reacting a benzophenone of the general formula Ra (III) wherein R R and R are as described above with a compound of the general formula ll X-C-CHO O O-lower alkyl NHRO (1v) wherein R is any suitable leaving group, preferably a wherein R R R and R are as described above.

The compounds of Formula V above can then be converted into the desired compounds of Formula II by effecting ring closure of said compounds. This ring closure of the compounds of Formula V above can be accomplished in several ways. For example treating the compounds of Formula V above with a hydrohalic acid, such as hydrobromic acid, or with glacial acetic acid yields the desired compounds of Formula II directly.

Alternately, the ring closure of the compounds of Formula V above can be accomplished by treating said compounds with a base, thereby obtaining compounds of the general formula 0/0 0 O-lower alkyl H (VI) wherein R R R and R are as described above tained with a hydrohalic acid, such as hydrobromic acid, to obtain the desired compounds of Formula II. Suitable bases for this process aspect of the present invention are organic bases such as alcoholates, i.e. sodium methoxide and the like, triethylamine and pyridine, and inorganic bases such as potassium carbonate and the like.

In a further process aspect of the present invention, the compounds of Formula II above can also be prepared by reacting a benzophenone of Formula III above wherein.R signifies hydrogen or halogen, i.e. a compound of the formula in NH in (1112.) wherein R is hydrogen or halogen and R and R are as described above with a malonic acid ester halide of the general formula XCHJCH2G O 0-lower alkyl wherein X is halogen I (VII) whereby to obtain a compound of the general formula 'mulae IIIa and VII above may be effected in the presence or absence of an acid acceptor. If an acid acceptor is utilized, suitable acid acceptors for this purpose are, for example, bicarbonates such as sodium bicarbonate and the like, and triethylamine.

The compounds of Formula VIII obtained as described above may then be nitrated or nitrosated to produce compounds of the general formula R I NC:

I ia (IX-a) (IX-b) wherein R R and R areas described above.

The nitration or nitrosation of the compounds of Formula VIII above to produce the corresponding compounds of Formula IXa or IXb above is expediently carried out with nitric acid or nitrous acid, for example, provided by the addition of sodium nitrite to glacial acetic acid in accordance with the conventional procedures. The

reaction is preferably effected at room temperature, although temperatures above and below room temperature can also be employed. The nitration or nitrosation re- .and then treating the compounds of Formula VI so ob- .6 action is preferably effected in the presence of a solvent. Suitable solvents for this purpose include hydrocarbons or chlorinated hydrocarbons such as methylene chloride and the like. i

The resulting compounds of Formula IXa or IXb prepared as described above may then be reduced to yield the desired compounds of Formula II above. The reduction of compounds of Formula IXa or IXb can be effected by conventional means as, for example, by treating said compounds with zinc in glacial acetic acid or zinc in ammonium chloride. Here again the reaction is preferably efi'ected in the presence of an inert organic solvent such as a hydrocarbon, e.g. benzene, toluene and the like, a chlorinated hydrocarbon, e.g. methylene chloride and the like, an ether, e.g. dioxane, or an alcohol, e.g. methanol, ethanol and the like. The reaction is preferably effected at temperatures between 0 C. and reflux temperature of the reaction mixture. It is assumed that this reduction reaction proceeds via the formation of a hydroxylamine intermediate product.

The compounds of Formula II, prepared by any of the procedures discussed above, may, in part, be present in the form of the corresponding open compounds, i.e. compounds of the general formula wherein R R and R are as described above.

Example 1 A suspension of 16 g. of 2-carbomethoxy-N-(benzyloxycarbonyl) glycine in ml. of dry methylene chloride, cooled to 20, is treated with 12.6 g. of phosphorus. pentachloride. After the mixture has been stirred at 20 to 10 for 30 minutes, 9.8 g. of 5-chloro-2-methylarnino-benzophenone are added to the now clear solution. r r v 200 ml. of 10% aqueous soda solutionare thereupon added dropwise at 0-5 with strong stirring during 15 minutes. After-the addition, the mixture is further stirred at 1015 for 15 minutes.

The methylene chlorine phase is separated 01f, washed with saturated sodium bicarbonate solution, dried over anhydrous sodium sulphate and evaporated. There is obtained a slightly yellow-coloured resin (23.8 g.) of crude 2'-benzoyl 2 [(benzyloxycarbonyl)amino] 2 carbomethoxy-4chloro-N-methylacetanilide. A solution of 7.5 g. of this resinin 40 ml. ofabsolute methanol is treated with 0.2 ml. oftriethylamine and allowed to stand at room temperature for 18 hours. The product crystallized out is filtered off by suction, washed With methanol and dried in vacuum. 3-[(benzyloxycarbonyl)amino]-3-carbomethoxy 6 chloro 4 hydroxy 1 methyl-Z-oxo-4- phenyl 1,2,3,4 tetrahydroquinoline, melting point 177- 180 C., is obtained after recrystallization from methylene chloride/hexane.

10 g. of 3 [(benzyloxycarbonyl) amino] 3 carbomethoxy 6 chloro 4 hydroxy 1 methyl-'2-oxo-4- phenyl-,1,2,3,4tetrahydro-quinoline arev dissolved in a mixture of 50 ml. of methylene chloride and 50 ml. of glacial acetic and treated with 40 ml. of hydrogen bromide in glacial acetic acid (ca. 30%). After standing overnight at room temperature, themixture is concentrated in vacuum, the hydrobromide of 3-amino-3-carbomethoxy 6 chloro 4 hydroxy 1 methyl-2-oxo4- phenyl l,2,3,4 tetrahydro quinoline being obtained in crystalline form. This is suspended in absolute ether, filtered off by suction, washed with absolute ether and dried, yielding the product, M.P. l43-l47 (dec.).

For the preparation of the base, the hydrobromide is partitioned between methylene chloride and aqueous soda solution. The dried organic phase is evaporated and the residue crystallized from ether, yielding 3-amino-3-carbomethoxy 6 chloro 4 hydroxy 1 methyl-2-oxo-4- phenyl l,2,3,4 tetrahydro-quinoline, melting point 125- In analogous manner, starting from Z-carbethoxy-N- (benzyloxycarbonyl) glycine there can be manufactured 3-amino-3-carbethoxy 6 chloro 4 hydroxy-l-methyl 2-oxo-4-phenyl l,2,3,4 tetrahydro-quinoline of melting point 150-152 C.

Example 2 0.5 g. of 3-amino-3-carbomethoxy-6-chloro-4-hydr0xy- 1 methyl-2-oxo-4-phenyl-l,2,3,4-tetrahydroquinoline are boiled under reflux for 3 hours in 20 ml. of absolute benzene in the presence of 2 ml. of glacial acetic. After evaporation in vacuum, the crystalline residue is recrystallized from methylene chloride-methanol. 0.43 g. of methyl 7-chloro-2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H- 1,4-benzodiazepine-3-carboxylate of M.P. 224-226 are obtained.

In analogous manner, from 3-amino-3-carbethoxy-6- chloro-4-hydroxy l methyl-2-ox0-4-phenyl-l,2,3,4-tetrahydroquinoline there is obtained ethyl 7-chloro-2,3-dihydro 1 methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepine- 3-carboxylate.

Example 3 12.6 g. of phosphorus pentachloride are added to a suspension of 16 g. of 2-carbomethoxy-N-(benzyloxycarbonyl)glycine in 100 ml. of methylene chloride, cooled to 20. After the mixture has been stirred at --20 to 10 for 30 minutes, 9.3 g. of 2-amino-5-chloro-benzophenone are introduced. 100 ml. of 10 percent soda solution are allowed to run in with vigorous stirring and the mixture is further stirred at -10 for 30 minutes. The methylene chloride phase is separated off, washed with bicarbonate solution, dried over sodium sulphate and evaporated. Crystallization of the residue from methanol yields 17.5 g. of 2-benzoyl-2-carbomethoxy-Z-[(benzyloxycarbonyl)amino]-4'-chloro-acetanilide which melts at 1l0ll2 after recrystallization from methanol.

20 ml. of a 30 percent solution of hydrogen bromide in glacial acetic acid are added to a solution of 5 g. of 2-benzoyl 2 [(benzoyloxycarbonyl)amino] 2 carbomethoxy-4'-chloro-acetanilide in 30 m1. of glacial acetic acid. After standing at room temperature for 16 hours, the mixture is evaporated in vacuum and the residue partitioned between water and ether. The aqueous phase is washed with ether and made alkaline with soda solution. The base which separates out is extracted with methylene chloride. The methylene chloride extracts, dried over sodium sulphate, yield, after evaporation in vacuum, 3.5 g. of residue from which 2.7 g. of 3-amino-3-carbomethoxy 6 chloro 4 hydroxy-2-oxo-4-phenyl-1,2,3,4- tetrahydroquinoline, M.P. 162l67 C., are obtained by crystallization from ether. The product melts at 168- 170 C. after recrystallization from methylene chloridemethanol-ether.

Example 4 47 g. of phosphorus pentachloride are added to a suspension of 74 g..of 2-carbethoxy-4-(benzyloxycarbonyl) glycine in 400 ml. of methylene chloride, cooled to 20 C. The mixture is stirred at 20 C. for 2 hours, and thereupon 58 g. of 2-amino-S-nitrobenzophenone, 2 ml. of dimethylformamide in 150 ml. of methylene chloride are introduced. The methylene chloride is evaporated off with vigorous stirring (-70 C.). The residue is extracted with methylene chloride-10% soda solution, the methylene chloride phase dried over magnesium sulphate and evaporated. The yellow-colored resin is stirred in 200 ml. of hydrogen bromide-acetic acid (30%) for 2 hours at room temperature and concentrated in vacuum. An analytical sample is crystallized from ethanol-ether, the hydrobromide of 3-amino-3-carbethoxy-6-nitro-4-hydroxy-2-oxo-4- phenyl-1,2,3,4-tetrahydroquinoline, melting point 188 (dec.), being obtained. For the preparation of the base, the crude mixture is partitioned between ether and water and extracted three times with ether. The water phase is made alkaline with 10 percent soda solution and extracted with methylene chloride. The dried organic phase is evaporated and the residue directly further processed.

Example 5 A solution of 23 g. of Z-amino-S-chlorobenzophenone in 200 ml. of methylene chloride is overlaid with ml. of saturated sodium bicarbonate solution. 19.3 g. of 2-carbethoxyacetyl chloride are added dropwise with vigorous stirring at 05. After the addition is completed, the mixture is stirred for an additional 10 minutes. The methylene chloride phase is separated off, washed with bicarbonate solution, dried over sodium sulphate and evaporated. The residue is crystallized from ether-hexane by cooling to -10. After filtering off by suction and drying in vacuum, there is obtained colourless ethyl 2-benzoyl-4'-chloromalonanilate, M.P. 54-55 Example 6 A solution of 34.6 g. of ethyl 2-benzoyl-4'-chloromalonanilate in 250 ml. of glacial acetic acid is treated at 20 with 30 m1. of fuming nitric acid (98%). After 2 /2 hours standing at room temperature, the reaction mixture is poured onto 1 liter of water. The precipitated resin is separated oil from the water phase, washed with water and taken up in ether. The ethereal solution is repeatedlyextracted with saturated bicarbonate solution. The extracts, washed out with ether, are acidified with hydrochloric acid and the nitro compound which separates out is extracted with methylene chloride. The extracts, dried over sodium sulphate, yield, after evaporation, a yellow resin of ethyl 2'-benzoyl-4-chloro-2-nitromalonanilate which is directly further reacted.

A solution of 2 g. of crude ethyl 2-benzoyl-4-chloro-2- nitro-malonanilate in 50 ml. of methylene chloride is successively treated with 2 ml. of glacial acetic acid and 2 g. of zinc dust.

After the strongly exothermic reaction (reflux of the solvent), the mixture is stirred for an additional 10 minutes. After filtration, the filtrate is evaporated and the residue taken up in 70 ml. of benzene, treated with 2 ml. of glacial acetic acid and boiled under reflux for 2 hours.

The reaction mixture is washed out with saturated so dium bicarbonate solution, dried over sodium sulphate and evaporated. Crystallization of the residue from alcohol yields ethyl 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-Z-one 3-carboxylate, M.P. 228-230". Further ethyl 7-chloro 1,3 dihydro-S-phenyl-ZH-1,4-benzodiazepin-2-one-3-carboxylate can be obtained from the mother liquor.

Example 7 A solution of 50 g. of sodium nitrite is added dropwise to a solution of 34.6 g. of ethyl 2'-benzoyl-4'-chloromalonanilate in 250 ml. of glacial acetic acid. After 1 /2 hours stirring at room temperature, the oxime crystallizes out and is filtered olf by suction, washed with water and dried in vacuum. Ethyl 2-benzoyl-4-chloro-mesoxalanilate 2-oxime, M.P. 98-105 is obtained.

Water is added dropwise to the filtrate with stirring, whereby further oxime crystallizes out.

According to thin layer chromatog'ram, the crude product consists of a mixture of the two stereoisomeric oximes. These may be separated by chromatography on Kieselgel with 20% acetic ester in methylene chloride. The first eluted isomer melts at 115-117 after crystallization from alcohol-water. The oxime eluted later shows a M.P. of l3l-l32 after crystallization from ether'hexane.

A solution of 2 g. of ethyl 2'-benzoyl-4'-chloro-mesoxalanilate 2-oxime in 40 ml. of methylene chloride is treated with 2 g. of zinc dust. 4 ml. of glacial acetic acid are added dropwise within 5 minutes with stirring. After the addition, the mixture is stirred at room temperature for 1 hour. The reaction mixture is filtered and the filtrate evaporated. The residue is boiled under reflux for 2 hours in 20 ml. of benzene and 2 ml. of glacial acetic acid. The reaction mixture is washed out with soda solution, dried over sodium sulphate and evaporated. Crystallization of the residue from alcohol yields ethyl 7-chloro-1,3- dihydro-S-phenyl 2H 1,4 benzodiazepin-2-one-3-carboxylate, M.P. 232-234". Furthermore material crystallizes from the mother liquor.

Example 8 tion are added with vigorous stirring within minutes I at 05 C. The organic phase is separated olf, washed with bicarbonate solution and water, dried over sodium sulphate and evaporated in vacuum. The residue crystallizes from ether-hexane. Colourless crystals of ethyl 2'- benzoyl- '-chloro-N-methyl-malonanilate, M.P. 98-100 H are obtained. Example 9 A solution of 36 g. of ethyl 2'-benzoyl4'-chloro-N- methyl-malonanilate in 250 ml. of glacial acetic acid is treated with 30 ml. of fuming nitric acid (98%). After 2 hours standing at room temperature, the reaction mixture is poured onto 1 liter of water. The resin which separates out is separated 01f, washed with water and taken up in benzene. The benzene solution is washed with water, dried over sodium sulphate and evaporated. The resinous residue of ethyl 2'-benzoyl 4-chloro-2-nitro-N-methylmalonanlilate is directly further reacted.

2 g. of zinc dust are introduced with stirring into a solution of 2 g. of ethyl 2'-benzoyl 4'-chloro-2 ntitro-N- methyl-malonanilate and 2 ml. of glacial acetic acid in 50 ml. of methylene chloride. After the exothermic reaction, the mixture is stirred for 10 minutes, filtered and evaporated. The residue is taken up in benzene and the solution extracted 3 times with 2 N hydrochloric acid. The extracts, back-washed with ether, are made alkaline with 10% soda solution and the bases which separate out extracted with methylene chloride. The extracts are dried over sodium sulphate and evaporated. The residue is dissolved in ml. of benzene. After addition of 2 ml. of glacial acetic acid, the solution is boiled under reflux for 2 hours. The cooled solution is washed out with soda solution, dried over sodium sulphate and evaporated. Crystallization of the residue obtained from alcohol yields ethyl 7-chloro 1,3 dihydro-1-methyl-5-phenyl-2H1,4-benzodiazepin-2-one-3-carboxylate, M.P. 196499".

Example 10 A solution of 18 g. of ethyl 2'-benzoyl-4'-chloro-.N- methyl-malonanilate in 125 ml. of glacial acetic acid is treated with a solution of g. of sodium nitrite in 50 ml. of water. 10 ml. of conc. sulphuric acid are added dropwise to the stirred reaction mixture. After the mixture has been stirred at room temperature for 2 hours, the product is crystallized out by addition of water, filtered off by suction and dried in vacuum. Ethyl 2'-benzoyl-4'-chloro-N-methyl-mesoxalanilate 2 oxime, M.P. 196-198" is obtained. Pure oxime recrystallized from benzeneacetic ester melts at 203-205".

2 g. of zinc dust are added to a solution of 2 g. of ethyl 2' benzoyl-4-chloro-N methyl-mesoxalanilate 2- oxime in 40 ml. of methylene chloride. 4 ml. of glacial acetic acid are added dropwise during 5 minutes with stirring. After the addition, the mixture is further stirred at room temperature for 30 minutes. The reaction mixture is filtered and evaporated. The residue is boiled under reflux for 2 hours in 20 ml. of benzene and 2 ml. of glacial acetic acid. The benzene solution is thereupon Washed with 10% soda solution, dried over sodium sulphate and evaporated. Crystallization of the residue from alcohol-ether yields ethyl 7-chloro-1,3-dihydro-l-methyl- 5-phenyl-2H-1,4-benzodi azepin-2-one-Z-carboxylate, M.P. 195-197 Example 11 12.5 g. phosphorous pentachloride were added to a solution of 17 g. 2-carbethoxy-N-(benzyloxycarbonyl)- glycine in 150 ml. methylene chloride cooled to 20. The mixture was stirred at '-20 until a clear solution resulted. A solution of 12.5 g. Z-amino-5-chloro-2-fluorobenzophenone in ml. methylene chloride was added followed by dropwise addition of 100 ml. aqueous sodium carbonate (10%) with vigorous stirring. Stirring was continued for 2 /2 hours while the temperature was allowed to rise to 20. The pH of the aqueous phase was kept at 7-8 by the addition of sodium carbonate. After dilution with water and methylene chloride, the organic layer was separated, washed with water, dried over magnesium sulfate and evaporated. The residue was crystallized from ethanol ether and recrystallized from ethanol to yield ethyl 2-[1-(benzyloxy)formamido]-2-(o-fluorobenzoyl)-4-chloro-malonanilate with M.P. l06l07.

Example 12 5 g. ethyl-2-[1 (benzyloxy)formamido]2'-(o-fiuorobenzoyl)-4'-chloro-malonanilate were suspended in 15 ml. acetic acid containing 30% hydrogen bromide. The suspension was stirred at room temperature until solution was complete (1-2 hours). The mixture was poured on 2 N sodium hydroxide and ice and extracted with methylene chloride. The extracts were dried over magnesium sulfate, filtered and evaporated. The residue was dissolved in ethanol and allowed to crystallize in the refrigerator overnight to yield ethyl 3-amino-6-chloro-4-hydroxy-4- (ofluorophenyl)-2-oxo-l,2,3,4-tetrahydroquinone 3 carboxylate with M.P. 169170 dec.

Example 13 30.8 g. phosphorouspentachloride were added at .20 to a suspension of 42 g. of 2-carbomethoxy-N-(benzyloxycarbonyl)glycine in 150 ml. methylene chloride. After the suspended material had dissolved (about /2 hour) a solution of 25 g. of 2-amino-2-fluoro-S-nitro-benzophenone in 150 ml. methylene chloride containing 3 drops of dimethylformamide was added. The reaction mixture was concentrated on the rotary evaporator at 40 to 50. The residue was distributed between methylene chloride and saturated aqueous sodium bicarbonate solution containing crushed ice. The methylene chloride layer was separated, washed with water, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel with methylene chloride. Crystallization from ether-ethanol yielded ethyl-2-[1-(benzyloxy)formamido]-2-(ofluorobenzoyl)-4-nitromalonanilate with M.P. 104.

Example 14 5 6 g. ethyl-2-[ 1-(benzoyloxy)-formamido]-2'-(o-fluorobenzoyl)-4-nitromalonanilate were stirred at room temperature for 1 hour in ml. glacial acetic acid containing 30-33% hydrogen bromide. The solvent was evaporated under reduced pressure and the residue was distributed between water and ether. The aqueous phase was made alkaline by addition of sodium bicarbonate solution and extracted with methylene chloride. The extracts were dried over magnesium sulfate and evaporated. The residue was crystallized from ether to yield ethyl 3-amino-4-hydroxy-6-nitro-4-(o-fluorophenyl)-2-oxo 1,2,3,4 tetrahydroquinoline-3-carboxylate with M.P. 163 dec.

Example 15 2.1 g. phosphorous pentachloride were added at 20 to a suspension of 2.81 g. Z-carbethoxy-N-(benzyloxycarbonyl)-glycine in 20 ml. methylene chloride. The mixture was stirred until solution was complete. 2.5 g. 2-(2-amino- -bromobenzoyl)-pyridine dissolved in 40 ml. methylene chloride were added followed by aqueous sodium carbonate. After stirring for 2 hours at 0, the methylene chloride layer was separated, washed with water, dried, filtered and evaporated. The residue was crystallized from ethanol to yield benzyl 6-bromo-3-(ethoxycarbonyl)-4-hydroxy-2-oxo-4-(2-pyridyl)-1,2,3,4-tetrahydroquinoline 3- carbamate with M.P. 204-208.

Example 16 1.5 g. benzyl 6-bromo-3-(ethoxycarbonyl)-4-hydroxy-2- oxo-4-(2-pyridyl)1,2,3,4-tetrahydroquinoline 3 carbamate were stirred for 1 hour at room temperature in 10 ml. glacial acetic acid containing 30-33% hydrogen bromide. The reaction mixture was concentrated under reduced pressure and the residue washed several times with anhydrous ether to leave ethyl 3-amino-6-bromo-4-hydroxy-2-oxo-4-(2-pyridyl)-1,2,3,4-tetrahydroquinoline 3- carboxylate with M.P. 220 dec.

Example 17 0.8 g. sodium methoxide were added to a solution of 2.7 g. ethyl 3-amino-6-chloro-4-hydroxy-4-(o-fluorophenyl)- 2-oxo-1,2,3,4-tetrahydroquinoline-3-carboxylate in ml. dimethylformamide cooled to 20. Having stirred for /2 hour at 20, the temperature was lowered to 40 and 1.5 g. diethylaminoethyl chloride were added. Stirring was continued for 1 hour at -40 and for 1 hour at room temperature. The reaction mixture was poured on ice water and extracted with methylene chloride. The organic layer was dried over magnesium sulfate, filtered and evaporated. The residue was dissolved in benzene and the solution was extracted twice with 1 N hydrochloric acid. The acid extracts were made alkaline by addition of sodium carbonate and extracted with methylene chloride. The methylene chloride layer was dried, filtered and concentrated to leave an oil of ethyl 3-amino-6-chloro-1-(Z-diethylaminoethyl)- 4-hydroxy-4-(o-fiuorophenyl)-2-oxo-1,2,3,4 tetrahydroquinoline-3-carboxylate which was purified by chromatography on 20 g. silica gel using methylene chloride/ethyl acetate followed by acetone for elution.

1 2 We claim: 1. A compound of the formula wherein D is hydrogen, lower alkyl having from 1 to 4 carbon atoms, or dialkylamino-lower alkyl wherein the lower alkyl moiety has from 1 to 4 carbon atoms; R is phenyl, mono-halo-phenyl or pyridyl; R is hydrogen, halogen or nitro; and the lower alkyl moiety of the carbalkoxy group has from 1 to 4 carbon atoms.

2. A compound of claim 1 wherein R is phenyl or 2- halophenyl.

3. A compound of claim 1 wherein R is methyl, R is phenyl and R is chlorine, i.e., 3-amino-3-carbalkoxy-6- chloro-4-hydroxy-1-methyl-2-oxo-4-phenyl-l,2,3,4 tetrahydroquinoline.

4. The compound of claim 1 wherein R is methyl, R is phenyl, R is chlorine and the carbalkoxy group is carbomethoxy, i.e. 3-amino-3-carbomethoxy-6-chloro 4 hydroxy-l-methyl-2-oxo-4-phenyl-1,2,3,4 tetrahydroquinoline.

5. A compound of claim 1 wherein R is hydrogen, R is phenyl and R is nitro, i.e., 3-amino-3-carbalkoxy-6- nitro-4-hydr0Xy-2-oxo-4-phenyl-1,2,3,4 tetrahydroquinoline.

6. The compound of claim 1 wherein R is hydrogen, R is phenyl, R is nitro and the carbalkoxy group is carbethoxy, i.e., 3-amino-3-carbethoxy-6-nitro-4-hydroxy-2- oxo-4-phenyl-1,2,3,4-tetrahydroquinoline.

7. A compound of claim 1 wherein R is diethylaminoethyl, R is 2-fiuorophenyl and R is chlorine, i.e., 3-amino- 3-carbalkoxy-6-chloro-4-hydroxy-l-diethylaminoethyl 2- oxo-4-(2-fiuorophenyl)-1,2,3,4-tetrahydroquinoline.

References Cited UNITED STATES PATENTS 1/1972 Suh 260-288 R 6/ 1972 Hellerbach 260287 R OTHER REFERENCES DONALD G. DAUS, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT @FFKQE EQ'H CERTIFICAT w m Dated' 11/13/73 Patent No. 3,772,305

{Inven Joseh Hel e o It is certified that: error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I Colume 12 line 11 of Letters Patent claim 1 "wherein D should be whez ein R Signed and sealed this 8th day of October 1974.

Attest:

MCCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-P69 A U.S. GOVERNMENT PRINTING OFFICE 1969 O366-334,

FORM PO-IOSO (IO-69) 

